Daily Review #4 Describe the 4 different pieces of evidence to support continental drift How does...
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Transcript of Daily Review #4 Describe the 4 different pieces of evidence to support continental drift How does...
Daily Review #4Describe the 4 different pieces of
evidence to support continental drift
How does convection cause a plate to move?
Discuss your answer to the writing prompt about what you think will happen to the continents in 100 million years.
Plate TectonicsMovement
◦cm/yr◦Measured
by GPSInteract at
boundaries – 3 types◦Collide◦Separate◦Slide past
Earthquakes can occur at all
ConvergentBoundary
Plates collideContinental-
continental◦ Create mountains
Continental-oceanic◦ Oceanic sinks◦ Subduction zone
and trench◦ Remelted, recycled
Oceanic-oceanic◦ One subducts
Transform BoundaryPlates slide past eachNot usually smoothLarger, more
frequent earthquakes
Earthquakes
What are they? What is it like?
SeismologistWhere?
◦ Plate boundary◦ Rarely in middle
of continent◦ Occur at or
create faults◦ Varying depths◦ Focus
Epicenter
How are earthquakes measured?
Richter scale◦ Strength
(magnitude)◦ Measuring ground
motion◦ Used by the media
Moment magnitude◦ More precise◦ Measures the
energy released◦ Measured at the
epicenter◦ Used by scientists
Imaging of Earthquake Waves
Seismograph◦Shows local
movement
◦3 main waves1. P wave2. S wave3. Surface
waves
Finding the EpicenterDistance vs. time
graph is constant◦ Closest has
smallest time difference
Measure time difference on local seismograph◦ Compare to graph◦ Find distance
Repeat for multiple locations
Finding Epicenter cont.
Use distances found
Draw a circle from each site
Overlap = epicenter
Daily Review #5How are convergent and
transform boundaries similar? Different?
Give a current example of a convergent boundary and what is being formed there
What is an epicenter and how is it found?
What kind of damage can an earthquake cause and how do you think we could prevent that damage?
Elastic Rebound Hypothesis
Energy buildsEnergy
released◦Travel as
wavesRocks return
to original shape, but different locations
Earthquake Waves
P waves◦ First detected◦ Back-and-forth
S waves◦ Side-to-side◦ Slower, arrive later
Surface◦Rolling◦Side-to-side
◦Slowest◦More destructive
Aftershocks
Foreshocks
Earthquake Hazard Map
Earthquake PredictionNot exactSeismic gaps
◦Area of fewer earthquakes
◦Likely location of future earthquake
◦Used to predict 1989 San Francisco
Past frequency
Destruction from Earthquakes
Liquefaction◦ Mixing soil with
underground water◦ Sinkholes
LandslidesFire
◦ Broken gas and electrical lines
◦ Lack water to fight
Building and highway damage
TsunamiCause
◦Underwater earthquake
◦Ocean floor movement
Massive waves
Closer to shore◦Slows◦Increases in height
Tsunami warning system
Only a few a year
Most recent (major)◦Indonesia (Dec.
2004)◦Japan (Mar.
2011)Seiche